Defroster switch



Nov. 13, 1934. M. EHENNING DEFROSTER SWITCH Filed July 10, 1933 CUREEA/I S'UPPL Y cfzzvezzfaz Wake/272 7 W627??? liargeyf Patented N06. 13, 1934 UNITED STATES DEFROSTER SWITCH Malcolm E. Kenning, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa,

a corporation of Iowa Application July 10, 1933, Serial No. 679,681

12 Claims. (Cl. 200-83) An object of my present invention is to provide a defroster switch having novel means for using the defrosting mechanism and the control knob therefor for retaining the switch in a continuous operating position when desired.

Still a further object is to provide in connection with a switch having range adjustment, means for retaining the switch in a continuous operating position rather than its automatic cyclical operating positions, the same being effected by the same control knob which adjusts the range.

More particularly, it is my object to provide in a switch having a defroster in the form of a resisting member, means for abutting the switch mechanism to hold it in closed circuit position when desired, said resisting member being adjustable to act in such abutting capacity.

Still a further object is to provide in an automatic switch structure, a resisting and abutting element, which in one position is inoperative to either resist or abut a switch arm, in another position is effective to resiliently resist a part of the movement of the switch arm and in still another position abuts the switch arm to hold it in desired position against other tendencies to move it from such position.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 is a plan elevation of a switch structure embodying my invention, part of the cover being broken away to show the internal mechamsm.

Figure 2 is a front elevation of the same.

Figure 3 1s an enlarged sectional view on the line 3-3 of Figure 1.

Figure 4 is a similar view showing the parts in another position.

Figure 5 is a view of three of the elements shown in Figure 1 showing their positions changed.

Figure 6 is a similar view showing another position of the parts in Figure 5; and Figure '7 is a diagrammatic viewof my defroster switch connected in a refrigeration system.

0n the accompanying drawing, I have used the reference numeral 10 to indicate generally a switch housing. It is provided with a face plate 12 and a control knob 14.

The switch mechanism within the housing 10 is of ordinary character and comprises generally a pressure or temperature operated bellows 16, a primary switch arm 18 pivoted at 20, a secondary switch arm 22 pivoted at 24, an overcenter spring connection 26 between the switch arms and a switch blade 28. The switch blade 28 has a movable contact 30 for coaction with a fixed contact 32 for controlling an electric circuit, the switch structure being especially adapted for controlling the motor circuit of an electric refrigerating apparatus, depending on the temperature of the refrigerator, although it may be adapted for controlling other types of apparatus.

In Figure '7, I show electric refrigerating apparatus including a refrigerant compressor A, acondenser coil C and an evaporator E shown in the conventional manner. A bulb B is connected with a connection 15 of the temperature responsive element 16 for expelling or contracting the element 16 in response to temperature changes in the air flowing over the bulb B. A refrigerant compressor motor is indicated at M and it is controlled by the contacts 30 and 32 connected in series with it in the current supply circuit.

The primary switch arm 18 is engaged on one side by the bellows 16 and the bellows is opposed by a spring 34 which can be adjusted by the knob 14 for changing the range of operation of the switch. In connection with the switch arm 18, I

provide defrosting mechanism comprising a resisting and abutting or loading member A which is pivoted on the pin 20. The member A is provided with an adjusting screw 36 adapted to engage a stop 38 extending from the face plate 12. The knob 14, or rather an adjusting screw 40 extending from it, is provided with a cam 42 having a defroster depression a, a rim b and a lobe c. The member A has a cam engaging ear 44 adapted to coact with the parts a, b and c-of the cam 42.

In Figures 1 and 3, the depression a of the cam 42 registers with the car 44, permitting the adjusting screw 36 to strike the stop 38 due to the action of a loading spring 46. This causes a finger 41 on the member A to almosttouch the left side of a slot 45 in the arm 18 in Figure 1, so that during the latter part of the movement of the primary switch arm 18 in a right hand direction, the tension of the spring 46, which is adjustable by*a screw 48, will oppose the closing of the contacts 30 and 32, thus prolonging the de-energized cycle of the refrigerating mechanism and permitting the temperature of the refrigerator to rise and the cooling coil to consequently be defrosted.

When the temperature rises sufficiently to overcome the combined tensionsof the sprin s 34 re-establishing the refrigerator circuit.

When the rim b of the cam 42 registers with the ear 44, as in Figure 6, then the primary switch arm 18 is free to move to its opposite positions without the sides of the slot 45 striking the finger 41. Thus the knob 14 can be adjusted to any of the numbered positions on the face plate 12 (see Figure 2) without the spring 46 or the member A having any effect on the automatic operation of the switch.

In some installations, it is desirable to have the refrigerator operate continuously at the will of the operator. I therefore provide the continuous operation position indicated in Figure 2, inwhich position the lobe c of the cam 42. registers with the ear 44 of the member A to raise it to the position of Figure 5. In this position, the finger 41 engages the right side of the slot 45and either pulls the primary switch arm 18 to its on position, or retains it in on position if it is already there, each against the tendency of the spring 34 to move the switch to open circuit position when the bellows 16 contracts due to a cold condition of, the refrigerator. A stop 11 limits adjustment of the knob 14 by engagement with a pin 43 thereof.

After a period of continuous operation, which can'be of any length desired, the knob 14 can be returned to either the defrost position or one of the range adjusting positions (1 to 6).

From the foregoing construction, it is obvious that I have provided a very simple arrangement of mechanism for holding the switch in acontinuous operating position controllable by the range adjusting knob 14 which is also utilized for controlling the defrost position. The same mecha-, nism, including the member A which is used for defrosting, can, by the proper engagement of parts such as 41 and 45 and the proper proportioning thereof with respect to the various positions of the members.A and 18, be used for obtaining continuous operation as well as defrosting operation. 4

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. For use with a control mechanism including a cyclically operated movable member and adjustable means for adjusting the normal range thereof, a cam movable by said adjustable means, means in addition to said adjustable means for modifying the operation of a device controlled by said control mechanism to secure either a temporary non-normal operating cycle or continuous operation of said device comprising a resisting member cooperating with said cam when moved to a predetermined position to resist movement of said movable member for securing said nonnormal cycle ofoperation, said cam having a lobe to positively move said cyclically operated movable member to secure said continuous operation.

2. In combination with an automatically movable member and manually adjustable means movable between predetermined limits to vary the range thereof, mechanism for modifying the cycles of operation of said automatically movable. member and for securing non-cyclic operation thereof comprising a resisting and abutment member selectively movable to operative and in- I 1,980,524 and 46, then the contacts 30 and 32 will close for operative positions resisting and abutting said automatically movable member, said manually adjustable means being operatively associated 'therewith to render it resistingly operative to so modify said cycles of operation in one position of the manually adjustable means, to render itpositively and abuttingly operative in another position of said manually adjustable means and to render it resistingly and abuttingly inoperative in all other positions of the manually adjustable means.

3. In combination with an automatically movable member and manually adjustable means movable between predetermined limits to vary' the range thereof, mechanism for securing noncyclic operation thereof comprising an abutment member selectively movable to operative and inoperative positions, abutting said automatically movable member, said manually adjustable means being operatively associated therewith to render it positively and abuttingly operative in one position of the manually adjustable means and to render it abuttingly inoperative in all other positions of the manually adjustable means.

4. For use with an automatic control ,device having an alternately oppositely movable member, means to prolong the movement of said movable member in one direction comprising a springloaded member to be engaged by said movable member and manually operable means to set and retain it in position to be engaged thereby during the latterpart only of its movement in such direction to prolong movement of the movable member during such part of its movement or to set and retain it in position spaced therefrom whereby movement of the movable member is not so prolonged or to set and positively. retain it in position abutting said movable member to thus prevent movement of the movable member.

5. A control mechanism for refrigerators com- I prising a cyclically operated movable member, means for adjusting the normal range of said member, a cam in addition to and operated by said adjusting means to secure temporary noncyclic operation of the refrigerator, said earn 129 having an abutment to secure temporary continuous operation thereof and manually con--- trolledmeansfor rendering said cam efiective or ineffective to secure temporary non-cyclic operation and for moving said abutment to operative 5, position, said manually controlled means also serving to adjust said normal range adjusting means.

6. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, loading means therefor adjustable to one position for resiliently loading said switch arm during the latter part of its movement in one direction and adjustable to a positive position for moving it to its opposite position and/or retaining it there against the action of temperature to move it from such position.

7. In a switch structure, a switch arm movable automaticallydependent upon temperature conditions, loading means therefor adjustable to one W position for resiliently loading said switch arm 1 during the latter part of its movement in one direction and adjustable for moving it to its opposite position and/or retaining it there against the action of temperature to move it from such position, and a manually controllable element for adjusting said loading means to said resiliently loaded position or positively to said retaining position.

8. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, range adjusting means therefor and loading means therefor adjustable to one position for resiliently loading said switch arm during the latter part of its movement in one direction and adjustable for moving it to its opposite position and/or retaining it there against the action of temperature to move it from such position, and manually controllable means for adjusting said loading means to said resiliently loaded position or positively to said retaining position and for adjusting said range adjusting means.

9. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, loading means therefor adjustable to one position for defrosting purposes and to another position to move and/or positively retain said switch arm in closed circuit position.

10. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, loading means therefor and a cam having a depression cooperable with said loading means in one position of the cam for defrosting purposes and having a lobe cooperable with the automatically movable switch arm when the cam is in another position to move and positively retain it in closed circuit position.

11. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, a movable modifying member therefor, loading means for said modifying member and a cam cooperable with said modifying member and adjustable to one position permitting action of said. loading means thereon for defrosting purposes and to another position to move and positively retain said modifying member and thereby said switch arm in closed circuit position.

12. In a switch structure, a switch arm movable automatically dependent upon temperature conditions, loading means therefor and a cam adjustable to one position for permitting said loading means to affect said switch arm during the latter part of its movement in one direction and adjustable to a positive position for moving the switch arm to its opposite position and retaining it there against the action of temperature to move it from such position.

MALCOLM E. HENNING. 

